1. Field of the Invention
The invention pertains to a seal ring formed of a plurality of layered materials. More particularly, the seal ring is formed as an O-ring having an intermediate layer to reduce permeation of fluids or gasses through the seal ring while retaining sealing capabilities and properties.
2. Description of the Related Art
Seals are used to seal a variety of mechanical parts. Normally, a seal is a pliable member, having some resiliency, that is placed between two rigid parts to prevent the escape or migration of a fluid or gas. One type of such a seal is an O-ring. Typically, an O-ring is a ring of elastomeric material used to seal a moving part within a housing or enclosure. One typical use for an O-ring would be in a hydraulic cylinder, wherein the O-ring seals the piston within the cylinder such that the hydraulic fluid moves the piston. Additionally, O-rings are used to seal fluid-type connections wherein fluid is being passed through one tubular member to a second tubular member or conduit.
It is known to manufacture O-rings of dissimilar materials. See for example U.S. Pat. No. 2,961,713 which discloses laminating sheets of different colored materials together and using conventional compression cavity molding techniques to form an O-ring. However, such an approach is limited in that it requires the use of common cure system material. Such materials are necessary in order to obtain cross linkage; i.e., a suitable bond between the materials used. Only common cure materials or those which will cross link with one another may be used.
While such an O-ring is suitable for some purposes, it is desirable to have an O-ring having a high resistance to permeability of certain fluids and gasses while at the same time exhibiting sufficient elastability and resiliency to provide a suitable fluid or gas seal. Obviously, many materials which are suitable for providing a proper seal may not have the necessary properties to resist permeability.